在有序半孔碳上评估共价修饰表面氨基的酸性和性反性
Nolan C Kovach1, Scott Edward Massimi1, Jayson Foster1
1Department of Chemistry, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States.
Langmuir : the ACS journal of surfaces and colloids
|June 13, 2024
概括
使用丁将氨基基组植入有序半孔碳 (OMC) 表面,在强酸和中稳定. 氧化植入只能在强的基中稳定,这凸显了对碳材料的化学测试的需要.
科学领域:
- 材料科学 材料科学 材料科学
- 表面化学 表面化学
- 纳米技术 纳米技术
背景情况:
- 订制半孔碳 (OMC) 材料为各种应用提供可调节的多孔性和高表面积.
- 用氨基组对OMC的表面修饰对于催化,吸附和传感等应用至关重要.
- 在恶劣的化学条件下,这些氨基表面的稳定性往往至关重要,但尚未完全理解.
研究的目的:
- 在OMC支架上研究两种不同的氨化方法的化学稳定性.
- 在酸性和基本条件下比较C-O-C (氧化合) 和C-C (有机金属激活合) 结合的氨基基团的稳定性.
- 强调对表面功能化碳材料进行严格的化学测试的重要性.
主要方法:
- 通过氧化合和有机金属激活合 (丁接种) 用初级氨基基组对OMC支架的共性修改.
- 化学应力测试通过浸泡在1M盐酸 (HCl) 和1M氧化物 (NaOH) 溶液中,在室温下进行6小时的化学应力测试.
- 使用吸附,电子显微镜,低角度X射线衍射,热重力测量分析和4-甲试验进行了表征.
主要成果:
- 通过丁接种 (C-C键) 创建的氨基化OMC表面在1M HCl和1M NaOH中表现出极好的稳定性.
- 通过氧化合 (C-O-C键) 产生的氨基化OMC表面在1M NaOH中显示稳定性,但在1M HCl中降解.
- 结果强调了基于氨化策略的化学强度的显著差异.
结论:
- 选择氨化化学方法对有序半孔碳表面的稳定性有深远的影响.
- 丁接种提供了一种强大的方法,用于创建氨基功能化OMC,适用于涉及强酸和的应用.
- 化学测试对于验证表面修改至关重要,特别是考虑到碳材料固有的异质性.
相关概念视频
01:21Basicity of Aliphatic Amines
5.8K
Amines can behave as Brønsted–Lowry bases by accepting a proton from the acid to form corresponding conjugate acids. Due to a lone pair of nonbonding electrons, aliphatic amines can also act as Lewis bases by forming a covalent bond with an electrophile.
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates...
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates...
5.8K
01:25Basicity of Heterocyclic Aromatic Amines
5.9K
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
5.9K
02:42Acidity of 1-Alkynes
9.7K
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
9.7K
01:18Basicity of Aromatic Amines
7.1K
The basicity of aromatic amines is much weaker than that of aliphatic amines due to the involvement of the lone pair of electrons over the N atom in resonance with the aryl rings. Generally, the electron-donating ability of any substituents on the aryl ring of aromatic amines increases the basicity of the amine by increasing electron density, and hence the availability of lone pair on the nitrogen. On the other hand, electron-withdrawing functional groups on the aryl ring of amines decrease the...
7.1K
01:23Aldehydes and Ketones with Amines: Imine Formation Mechanism
5.4K
Imine formation involves the addition of carbonyl compounds to a primary amine. It begins with the generation of carbinolamine through a series of steps involving an initial nucleophilic attack and then several proton transfer reactions. The second part includes the elimination of water, as a leaving group, to give the imine.
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
5.4K
01:38Preparation of Amines: Reductive Amination of Aldehydes and Ketones
2.8K
Carbonyl compounds and primary amines undergo reductive amination first to produce imines, followed by secondary amines in the same reaction mixture, using selective reducing agents like sodium cyanoborohydride or sodium triacetoxyborohydride. Reductive amination produces different degrees of substitution of amines depending on the starting amine substrate.
2.8K